Endometriosis occurs when cells from the lining of your womb (uterus) grow in other areas of your body. This can cause pain, heavy bleeding, bleeding between periods, and problems getting pregnant (infertility).
Every month, a woman's ovaries produce hormones that tell the cells lining the uterus to swell and get thicker. Your uterus sheds these cells along with blood and tissue through your vagina when you have your period.
Endometriosis occurs when these cells grow outside the uterus in other parts of your body. This tissue may attach on your:
Lining of your pelvic area
It can grow in other areas of the body, too.
These growths stay in your body--they do not shed when you have your period. But, like the cells in your uterus, these growths react to the hormones from your ovaries. They grow and bleed when you get your period. Over time, the growths may add more tissue and blood. The buildup of blood and tissue in your body leads to pain and other symptoms.
No one knows what causes endometriosis. One idea is that when you get your period, the cells may travel backwards through the fallopian tubes into the pelvis. Once there, the cells attach and grow. However, this backward period flow occurs in many women. Researchers think that the immune system in women with endometriosis may cause the condition.
Endometriosis is common. Sometimes, it may run in families. Endometriosis probably starts when a woman begins having periods. However, it usually isn't diagnosed until ages 25 - 35.
You are more likely to develop endometriosis if you:
Have a mother or sister with endometriosis
Started your period at a young age
Never had children
Have frequent periods or they last 7 or more days
Have a closed hymen, which blocks the flow of menstrual blood during the period
Pain is the main symptom of endometriosis. You may have:
Pain in your lower belly before and during your period
Cramps for a week or two before and during your period. Cramps may be steady and range from dull to severe.
Pain during or following sexual intercourse
Pain with bowel movements
Pelvic or low back pain that may occur at any time
You may not have any symptoms. Some women with a lot of tissue in their pelvis have no pain at all, while some women with milder disease have severe pain.
Exams and Tests
Your health care provider will perform a physical exam, including a pelvic exam. You may have one of these tests to help diagnose the disease:
Prescription painkillers, if needed, for more severe pain
Regular exams every 6 - 12 months so your doctor can make sure the disease is not getting worse
These medicines can stop endometriosis from getting worse. They may be given as pills, nasal spray, or shots. Only women who are not trying get pregnant should have this therapy. Hormone therapy will prevent you from getting pregnant. Once you stop therapy, you can get pregnant again.
Birth control pills. With this therapy, you take pills for 6 - 9 months without stopping. Taking these pills relieves most symptoms. However, it does not prevent scarring or treat any damage that has already occurred.
Progesterone pills or injections. This treatment helps shrink growths. However, side effects can include weight gain and depression.
Gonadotropin-agonist medications. These medicines stop your ovaries from producing the hormone estrogen. This causes a menopause-like state. Side effects include hot flashes, vaginal dryness, and mood changes. Treatment is usually limited to 6 months because it can weaken your bones.
Your doctor may recommend surgery if you have severe pain that does not get better with other treatments.
Laparoscopy helps diagnose the disease and can also remove growths and scar tissue. Because only a small cut is made in your belly, you will heal faster than other types of surgery.
Laparotomy involves making a large incision (cut) in your belly to remove growths and scar tissue. This is major surgery, so healing takes longer.
Laparoscopy or laparotomy may be a good option if you want to become pregnant, because they treat the disease and leave your organs in place.
Hysterectomy is surgery to remove your uterus, fallopian tubes, and ovaries. If your ovaries are not removed, symptoms may return. You would only have this surgery if you have severe symptoms and do not want to have children in the future.
Hormone therapy and laparoscopy cannot cure endometriosis. However, in some women, these treatments may help relieve symptoms for years.
Removal of the uterus, fallopian tubes, and both ovaries (a hysterectomy) gives you the best chance for a cure.
Endometriosis can lead to problems getting pregnant. However, most women with mild symptoms can still get pregnant. Laparoscopy to remove growths and scar tissue may help improve your chances of becoming pregnant. If it does not, you may want to consider fertility treatments.
Other complications of endometriosis include:
Long-term pelvic pain that interferes with social and work activities
Large cysts in the pelvis that may break open (rupture)
In rare cases, endometriosis tissue may block the intestines or urinary tract.
Very rarely, cancer may develop in the areas of tissue growth after menopause.
When to Contact a Medical Professional
Call for an appointment with your health care provider if:
You have symptoms of endometriosis
Back pain or other symptoms come back after endometriosis is treated
You may want to get screened for endometriosis if:
Your mother or sister has the disease
You are unable to become pregnant after trying for 1 year
Birth control pills may help to prevent or slow down the development of the endometriosis.
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de Ziegler D, Borghese B, Chapron C. Endometriosis and infertility: pathophysiology and management. Lancet. 2010 Aug 28;376(9742):730-8.
Susan Storck, MD, FACOG, Chief, Eastside Department of Obstetrics and Gynecology, Group Health Cooperative of Puget Sound, Bellevue, Washington; Clinical Teaching Faculty, Department of Obstetrics and Gynecology, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.